HomeMy WebLinkAbout31B_Geotech Engineer Of Record Letter_2023-0407G E O T E C H N I C A L E N G I N E E R I N G E N V I R O N M E N T A L E N G I N E E R I N G
C O N S T R U C T I O N T E S T I N G & I N S P E C T I O N
Offices Serving the Western United States
1230 Finn Hill Road NW, Ste. A, Poulsbo, Washington 98370 (360) 598-2126 • Fax (360) 626-3544
& A S S O C I A T E S , I N C .
April 7, 2023 Project No. 102-23007
Page 1 of 2
The Hamlet at Pleasant Harbor, LLC
308913 U.S. Highway 101
Brinnon, WA 98320
Attn: Mr. Don Coleman
Email:don@pleasanttharbormarina.com
Tel: (360) 796-4611
Reference: Geotechnical Engineer of Record (GEOR) Letter
Pleasant Harbor Development
308913 U.S. Highway 101
Brinnon, WA
Greetings:
Per your request we have prepared this GEOR letter for the Pleasant Harbor Development project located
at 308913 U.S. Highway 101 in Brinnon, Washington.
Introduction and Scope
We have reviewed the following project related geotechnical engineering documents and preliminary civil
drawings:
A geotechnical engineering report titled “Final Draft Geotechnical Investigation – Pleasant Harbor
Marina and Golf Resort – Jefferson County, Washington – Project No. SG0801”, prepared by
Subsurface Group, LLC, dated January 23, 2013.
An undated not to scale exhibit, Basins 1 through 10, prepared by Hatton Godat Pantier.
An undated draft subdivision/segregation plan, prepared by Hatton Godat Pantier.
Based on our communication with you, it is our understanding that you are planning to clear trees and brush
from the slopes of a depression in the central portion of the property, known as Kettle C. Jefferson County
is requiring an addendum to the Subsurface Group geotechnical engineering report regarding geologic
hazards associated with the planned clearing of the Kettle C slopes.
We have been requested to review the Subsurface Group geotechnical engineering report and, based on
their findings and evaluations, provide our engineering opinion regarding the applicability of their report to
the proposed development.
Exhibit 31B
KA Project No. 102-23007
GEOR Letter
Pleasant Harbor Development
April 7, 2023
Page No. 2
Krazan & Associates, Inc.
Offices Serving the Western United States
Review Notes and Conclusions
Based on the findings documented in the January 2013 geotechnical report by Subsurface Group, LLC,
Krazan and Associates, Inc., generally concurs with the with the opinions and recommendations presented
in the geotechnical report. The recommendations in Section 10.3.3 Seismic of the geotechnical report
would need to be updated to current International Building Code (IBC). Krazan can provide the updated
seismic recommendations in a separate letter.
A site visit for surficial visual reconnaissance of the Kettle C area was performed by our engineering
geologist on March 31, 2023. An unpaved road provides access to the bottom of the kettle. aside from the
grading associated with the access road, the kettle slopes appeared to be in a relatively undisturbed state.
We did not observe indications of significant sloughing or slope failure. The kettle slopes appeared to be
inclined at about 2H:1V (horizontal to vertical) to 1.5H:1V (50 to 66 percent). Based on the topographic
mapping of the site, the elevation ranges from about 100 feet to 180 feet. The kettle slopes were vegetated
with alder, cedar and maple trees with an understory of fern and salal. The test pits, TP-19 through TP-23,
monitoring well, MW-3, and infiltration test, IT-6 were all advanced and excavated in the Kettle C area.
The kettle slopes and bottom are interpreted to be underlain by native granular glacial soils. These granular
soils have low potential of erosion on relatively level surface when disturbed, and moderate potential on
slopes when disturbed. In our opinion, the clearing of trees and shrubs from the slopes should not cause a
significant increase in geologic hazards to the Kettle C slopes, provided that the recommendations of the
geotechnical engineering report and this letter are followed.
We recommend that removal of trees and brush should be performed during the dry weather, if feasible.
The tree and brush removal should be accomplished in sections, and erosion control measures should be
implemented as each section is cleared. We understand that the current plans do not include final grading
of the kettle slopes and liner placement, and recommend that Krazan should review the final grading plans
prior to the earthwork construction.
Krazan and Associates should monitor the slope clearing and erosion control implementation periodically.
CLOSURE
We appreciate the opportunity to provide this service for you. If you have any questions, or if we may be
of further assistance, please do not hesitate to contact our office at (360) 598-2126.
Respectfully submitted,
KRAZAN & ASSOCIATES, INC.
Vijay Chaudhary, P.E.
Project Engineer
VC:MDR
4/7/23
Exhibit 31B